Electronic apparatus and control method for electronic apparatus

ABSTRACT

In an electronic apparatus which includes a power generator and a storage device for storing electric energy obtained thereby, it is detected whether a motor driven by the stored electric energy is rotating by comparing the rotation detecting voltage, which is proportional to the induction voltage generated in the motor caused by the rotation of the motor, with a rotation reference voltage. The generation state of the power generator or the charging state of the storage device is detected. The level of the rotation detecting voltage or the level of the rotation reference voltage is shifted by a predetermined amount based on the detected generation state of the power generator or the detected charging state of the storage device so that the voltage difference between the rotation detecting voltage and the rotation reference voltage is increased during the no-rotation period.

TECHNICAL FIELD

The present invention relates to an electronic apparatus and a controlmethod therefor, and more preferably, to an electronic apparatus, suchas a portable electronic timepiece apparatus, having a built-in storagedevice and a drive motor, and to a control method for such an electronicapparatus.

BACKGROUND ART

Recently, small electronic timepieces, such as wristwatches, which havea built-in generator device, such as a solar cell, and which can beoperated without the need for replacing batteries have been realized.

These electronic timepieces are provided with a function of temporarilycharging power generated in the generator device into, for example, alarge-capacitance capacitor, and when power is not being generated, timeis indicated by the power discharged from the capacitor.

Accordingly, such electronic timepieces can be stably operated for along time without batteries, and by considering the effort required toreplace batteries and the problem of disposing of them, it can beexpected that many electronic timepieces will have a built-in generatordevice.

As such an electronic timepiece having a built-in generator device,there is an analog electronic timepiece disclosed in Japanese ExaminedPatent Publication No. 3-58073.

In this analog electronic timepiece, a rotation detecting circuit fordetecting the rotation of a motor used for driving hands is constructedin such a manner that a detection resistor device is selected from aplurality of detection resistor devices in accordance with theperformance of the motor.

In the above-described related art, in selecting the detection resistordevice in accordance with the performance of the motor, the followingproblem may occur. If a detection resistor device which increases thedetection sensitivity is selected, AC magnetic noise which is caused bythe operation of a generator device which would not normally be detectedin detecting AC magnetic fields is disadvantageously detected. As aresult, it may be erroneously detected that the motor is rotated, thoughit is not actually rotated.

Because of such erroneous detection, the driving of the motor cannot bereliably controlled.

Accordingly, it is an object of the present invention to provide anelectronic apparatus and a control method therefor in which the drivingof a motor can be reliably controlled by reducing the influence of noisecaused by, for example, a leakage flux of a generator device.

DISCLOSURE OF INVENTION

A first aspect of the present invention is characterized by including: apower generator portion for performing power generation; a storageportion for storing electric energy obtained by the power generation; asingle or a plurality of motors driven by the electric energy stored inthe storage portion; a pulse driving controller for controlling thedriving of the motor by outputting a driving pulse signal; a rotationdetecting portion for detecting whether the motor is rotating bycomparing a rotation detecting voltage corresponding to an inductionvoltage generated in the motor caused by the rotation of the motor witha rotation reference voltage; a state detecting portion for detecting ageneration state of the power generator portion or a charging state ofthe storage portion caused by the power generation; and a voltagesetting portion for setting the rotation detecting voltage or therotation reference voltage based on the generation state of the powergenerator portion or the charging state of the storage portion detectedby the state detecting portion so that a difference between the rotationdetecting voltage in a no-rotation period and the rotation referencevoltage is increased.

A second aspect of the present invention is characterized in that, inthe first aspect of the present invention, the voltage setting portionmay include a voltage shifting portion for relatively shifting thevoltage level of the rotation detecting voltage to a no-rotation side bya predetermined amount.

A third aspect of the present invention is characterized in that, in thefirst aspect of the present invention, the state detecting portion mayinclude a charging detecting portion for detecting whether the chargingis performed in the storage portion.

A fourth aspect of the present invention is characterized in that, inthe first aspect of the present invention, the state detecting portionmay include a power-generation magnetic-field detecting portion fordetecting whether a magnetic field is generated by the power generationof the power generator portion.

A fifth aspect of the present invention is characterized in that, in thesecond aspect of the present invention, the rotation detecting portionmay include a rotation-detecting impedance device, and the voltageshifting portion may include an impedance reducing portion foreffectively reducing the impedance of the rotation-detecting impedancedevice.

A sixth aspect of the present invention is characterized in that, in thefifth aspect of the present invention, the rotation-detecting impedancedevice may include a plurality of auxiliary rotation-detecting impedancedevices, and the impedance-reducing portion may effectively reduce theimpedance of the rotation-detecting impedance device by short-circuitingat least one of the plurality of auxiliary rotation-detecting impedancedevices.

A seventh aspect of the present invention is characterized in that, inthe fifth aspect of the present invention, the rotation-detectingimpedance device may include a plurality of auxiliary rotation-detectingimpedance devices, and the impedance-reducing portion may effectivelyreduce the impedance of the rotation-detecting impedance device byswitching the plurality of auxiliary rotation-detecting impedancedevices.

An eighth aspect of the present invention is characterized in that, inthe fifth aspect of the present invention, the rotation-detectingimpedance device may include a resistor device.

A ninth aspect of the present invention is characterized in that, in thefirst aspect of the present invention, there may be provided a chopperamplifier portion for performing chopper amplification on the inductionvoltage and for outputting the amplified induction voltage as therotation detecting voltage, and the voltage setting portion may includean amplification-factor reducing portion for reducing an amplificationfactor of the chopper amplifier portion based on the generation state ofthe power generator portion or the charging state of the storage portiondetected by the state detecting portion.

A tenth aspect of the present invention is characterized in that, in theninth aspect of the present invention, the amplification-factor reducingportion may include a voltage-drop-device inserting portion forinserting a voltage drop device in a path of a chopper current generatedby the chopper amplification.

An eleventh aspect of the present invention is characterized in that, inthe ninth aspect of the present invention, the chopper amplifier portionmay perform the chopper amplification at a frequency corresponding to achopper-amplification control signal, and the amplification-factorreducing portion may set the frequency of the chopper-amplificationcontrol signal in a detection period of a predetermined generation stateor a predetermined charging state caused by the power generation to behigher by a predetermined amount than the chopper-amplification controlsignal in a no-detection period of the predetermined generation state orthe predetermined charging state.

A twelfth aspect of the present invention is characterized in that, inthe ninth aspect of the present invention, the chopper amplifier portionmay set a chopper duty in a detection period of the charging to begreater or smaller than the chopper duty in a no-detection period of thecharging, which is a reference chopper duty.

A thirteenth aspect of the present invention is characterized in that,in the first aspect of the present invention, the voltage settingportion may include a voltage shifting portion for shifting the voltagelevel of the rotation reference voltage to a rotation side by apredetermined amount relative to the rotation detecting voltage based onthe generation state of the power generator portion or the chargingstate of the storage portion detected by the state detecting portion.

A fourteenth aspect of the present invention is characterized in that,in the thirteenth aspect of the present invention, the voltage shiftingportion may include a reference-voltage selecting portion for selectingone of a plurality of basic rotation reference voltages as the rotationreference voltage based on the generation state of the power generatorportion or the charging state of the storage portion detected by thestate detecting portion.

A fifteenth aspect of the present invention is characterized in that, inthe fourteenth aspect of the present invention, the state detectingportion may detect the charging state based on a charging currentflowing in the storage portion.

A sixteenth aspect of the present invention is characterized in that, inthe fourteenth aspect of the present invention, the state detectingportion may detect the charging state based on a charging voltage of thestorage portion.

A seventeenth aspect of the present invention is characterized in that,in the second aspect or the thirteenth aspect of the present invention,the pulse driving controller may output a rotation-detecting pulsesignal used for detecting the rotation by the rotation detecting portionafter the lapse of a predetermined period from an output of the drivingpulse signal, and the voltage shifting portion may set terminals of acoil forming the motor in a closed loop during the predetermined periodbased on the generation state of the power generator portion or thecharging state of the storage portion detected by the state detectingportion.

An eighteenth aspect of the present invention is characterized in that,in the seventeenth aspect of the present invention, the voltage shiftingportion may set a frequency of the driving pulse signal in a detectionperiod of a predetermined generation state or a predetermined chargingstate to be lower than a frequency in a no-detection period of thepredetermined generation state or the predetermined charging state basedon the generation state of the power generator portion or the chargingstate of the storage portion detected by the state detecting portion.

A nineteenth aspect of the present invention is characterized in that,in the second aspect or the thirteenth aspect of the present invention,the driving pulse signal may include a plurality of auxiliary drivingpulse signals, and the voltage shifting portion may set an effectivepower of the last auxiliary driving pulse signal in an output period ofthe driving pulse signal to be greater than an effective power of theother auxiliary driving pulse signal in the output period of the drivingpulse signal.

A twentieth aspect of the present invention is characterized in that, inthe first aspect of the present invention, the electronic apparatus maybe portable.

A twenty-first aspect of the present invention is characterized in that,in the first aspect of the present invention, the electronic apparatusmay include a timepiece portion for performing a timing operation.

According to a twenty-second aspect of the present invention, in acontrol method for an electronic apparatus which includes a powergenerator portion for performing power generation, a storage portion forstoring electric energy obtained by the power generation, a single or aplurality of motors driven by the electric energy stored in the storageportion, and a pulse driving controller for controlling the driving ofthe motor by outputting a driving pulse signal, the control method ischaracterized by including: a rotation detecting step of detectingwhether the motor is rotating by comparing a rotation detecting voltagecorresponding to an induction voltage generated in the motor caused bythe rotation of the motor with a rotation reference voltage; a statedetecting step of detecting a generation state of the power generatorportion or a charging state of the storage portion caused by the powergeneration; and a voltage shifting step of shifting the voltage level ofthe rotation detecting voltage to a no-rotation side by a predeterminedamount relative to the rotation reference voltage based on thegeneration state of the power generator portion or the charging state ofthe storage portion detected in the state detecting step.

According to a twenty-third aspect of the present invention, in acontrol method for an electronic apparatus which includes a powergenerator portion for performing power generation, a storage portion forstoring electric energy obtained by the power generation, a single or aplurality of motors driven by the electric energy stored in the storageportion, and a pulse driving controller for controlling the driving ofthe motor by outputting a driving pulse signal, the control method ischaracterized by including: a rotation detecting step of detectingwhether the motor is rotating by comparing a rotation detecting voltagecorresponding to an induction voltage generated in the motor caused bythe rotation of the motor with a rotation reference voltage; a statedetecting step of detecting a generation state of the power generatorportion or a charging state of the storage portion caused by the powergeneration; and a voltage shifting step of shifting the voltage level ofthe rotation reference voltage to a rotation side by a predeterminedamount relative to the rotation detecting voltage based on thegeneration state of the power generator portion or the charging state ofthe storage portion detected in the state detecting step.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating the configuration of atimepiece apparatus.

FIG. 2 is a block diagram illustrating the functional configuration of atimepiece apparatus of a first embodiment.

FIG. 3 is a diagram illustrating the portion close to a motor drivingcircuit and a rotation detecting circuit.

FIG. 4 is a schematic diagram illustrating an induction voltagecontroller.

FIG. 5 is a flow chart of the process of an embodiment.

FIG. 6 is a timing chart of the first embodiment.

FIG. 7 is a schematic diagram illustrating another induction voltagecontroller.

FIG. 8 is a schematic diagram illustrating still another inductionvoltage controller.

FIG. 9 illustrates the principle of a second embodiment.

FIG. 10 is a block diagram illustrating the functional configuration ofa timepiece apparatus of the second embodiment.

FIG. 11 is a timing chart illustrating the second embodiment.

FIG. 12 is a block diagram illustrating the functional configuration ofa timepiece apparatus of a third embodiment.

FIG. 13 is a block diagram illustrating the schematic configuration of arotation detecting circuit.

FIG. 14 is a timing chart of the third embodiment.

FIG. 15 is a block diagram illustrating the functional configuration ofa timepiece apparatus of a fourth embodiment.

FIG. 16 is a timing chart of the fourth embodiment.

FIG. 17 illustrates the operation of the fourth embodiment.

FIG. 18 is a diagram illustrating the portion close to a generationdetecting circuit of a fifth embodiment.

FIG. 19 is a diagram illustrating the detailed configuration of anexample of a rotation-detecting reference-voltage generating circuit ofthe third embodiment.

FIG. 20 is a timing chart illustrating a sampling signal.

BEST MODE FOR CARRYING OUT THE INVENTION

Preferred embodiments of the present invention are described below withreference to the drawings.

[1] First Embodiment

[1.1] Overall Configuration

FIG. 1 illustrates a schematic configuration of a timepiece apparatus 1,which is an electronic apparatus of a first embodiment.

The timepiece apparatus 1 is a wristwatch, which is used by a userwearing a strap connected to the main body of the apparatus around thewrist.

The timepiece apparatus 1 is largely formed of a generator unit A forgenerating AC power, a power supply unit B for rectifying the AC voltagefrom the generator unit A and storing the increased voltage and forsupplying power to the elements of the apparatus, a control unit C fordetecting the power-generation state of the generator unit A and forcontrolling the entire apparatus based on a detection result, ahand-moving mechanism D for driving hands, and a driving unit E fordriving the hand-moving mechanism D based on a control signal from thecontrol unit C.

In this case, according to the power-generation state of the generatorunit A, the control unit C switches between a display mode in which timeis indicated by driving the hand-moving mechanism D and a saving mode inwhich power is saved by interrupting the supply of power to thehand-moving mechanism D. The saving mode is forced to switch to thedisplay mode by the user shaking the timepiece apparatus 1 by hand. Theindividual elements are discussed below. The control unit C will bedescribed later by using functional blocks.

The generator unit A largely includes a generator device 40, anoscillating weight 45 which oscillates within the device in response tothe movement of a user's arm so as to convert dynamic energy torotational energy, and an accelerating gear 46 for converting(accelerating) the oscillation of the oscillating weight to a requirednumber of oscillations so as to transfer it to the generator device 40.

The oscillations of the oscillating weight 45 are conveyed to agenerator rotor via the accelerating gear 46 so as to rotate thegenerator rotor 43 within a generator stator 42. Accordingly, thegenerator device 40 serves as an electromagnetic-induction-type ACgenerator device for outputting power induced in a generator coil 44connected to the generator stator 42 to the outside.

Thus, the generator unit A generates power by utilizing energy relatedto the user's daily life so as to drive the timepiece apparatus 1 byusing the power.

The power supply unit B is formed of a diode 47, which serves as arectifier circuit, a large-capacitance capacitor 48, and a step-up/downcircuit 49.

The step-up/down circuit 49 increases or decreases the voltage inmultiple stages by using a plurality of capacitors 49 a, 49 b, and 49 cso as to adjust the voltage to be supplied to the driving unit E by acontrol signal φ11 from the control unit C.

An output voltage of the step-up/down circuit 49 is supplied to thecontrol unit C with a monitor signal φ12, thereby enabling the controlunit C to monitor the output voltage and to determine from a smallincrease or decrease of the output voltage whether the generator unit Ais generating power. The power supply unit B sets VDD (high potential)as a reference potential (GND) and generates VTKN (low potential) as apower supply voltage.

According to the above description, it is detected whether power isgenerated by monitoring the output voltage of the step-up/down circuit49 by using the monitor signal φ12. However, in a circuit configurationwithout a step-up/down circuit, it may be detected whether power isgenerated by directly monitoring the low-potential power supply voltageVTKN.

The hand-moving mechanism D is as follows. A stepping motor 10 used inthe hand-moving mechanism D, which is also referred to as a pulse motor,a stepper motor, a step motor, or a digital motor, is a motor which isoften used as an actuator of a digital control unit and is driven by apulse signal. These days, many smaller and lighter stepping motors arebeing used as actuators for use in portable-type small electronicapparatuses or information apparatuses. Typical examples of suchelectronic apparatuses are timepiece devices, such as electronictimepieces, time switches, and chronographs.

The stepping motor 10 of this example includes a driving coil 11 forgenerating a magnetic force by a driving pulse supplied from the drivingunit E, a stator 12 excited by this driving coil 11, and a rotor 13rotated by a magnetic field which is excited within the stator 12. Thestepping motor 10 is a PM type (permanent magnet rotation type) in whichthe rotor 13 is formed of a disc-type bipolar permanent magnet. Thestator 12 is provided with a magnetically saturated portion 17 so thatdifferent magnetic poles are generated in the corresponding phases(poles) 15 and 16 around the rotor 13 by the magnetic force generated bythe driving coil 11. Moreover, in order to define the rotating directionof the rotor 13, an inner notch 18 is provided at a suitable position inthe inner circumference of the stator 12, whereby a cogging torque isgenerated to stop the rotor 13 at a suitable position.

The rotation of the rotor 13 of the stepping motor 10 is conveyed to theindividual hands by a wheel train 50, which is formed of a fifth wheeland pinion 51, a fourth wheel and pinion 52, a third wheel and pinion53, a second wheel and pinion 54, a minute wheel 55, and an hour wheel56, meshed with the rotor 13 via the pinions. A seconds hand 61 isconnected to the shaft of the fourth wheel and pinion 52, a minute hand62 is connected to the shaft of the second wheel and pinion 54, and anhour hand 63 is connected to the shaft of the hour wheel 56. Time isindicated by these hands, operating in association with the rotation ofthe rotor 13. A transfer system (not shown) for displaying the day,month, and year may be connected to the wheel train 50.

Then, the driving unit E supplies various driving pulses to the steppingmotor 10 under the control of the control unit C. More specifically, byapplying control pulses having different polarities and pulse widths atdifferent times from the control unit C, driving pulses having differentpolarities, or detection pulses for exciting an induction voltage fordetecting the rotation and the magnetic field of the rotor 13, aresupplied to the driving coil 11.

[1.2] Functional Configuration of Control System

The functional configuration of the control system according to thefirst embodiment is now described with reference to FIG. 2.

In FIG. 2, symbols A through E correspond to the generator unit A, thepower supply unit B, the control unit C, the hand-moving mechanism D,and the driving unit E, respectively, shown in FIG. 1.

The timepiece apparatus 1 includes: a generator portion 101 forgenerating AC power; a charging detection circuit 102 for detectingcharging based on a generated voltage SK of the generator portion 101and for outputting a charging-detection result signal SA; a rectifiercircuit 103 for rectifying an alternating current output from thegenerator portion 101 and for converting it to a direct current; astorage device 104 for storing the direct current from the rectifiercircuit 103; and a timepiece control circuit 105, which is operated bythe electric energy stored in the storage device 104, for outputting anormal motor-driving pulse signal SI for performing timepiece controland also for outputting a generator AC magnetic-field detection timingsignal SB for designating the detection timing of the generator ACmagnetic field.

The timepiece apparatus 1 also includes: a generator AC magnetic-fielddetection circuit 106 for detecting the generator AC magnetic fieldbased on the charging-detection result signal SA and the generator ACmagnetic-field detection timing signal SB and for outputting a generatorAC magnetic-field detection result signal SC; a duty-reducing counter107 for outputting a normal-motor-driving-pulse duty-reducing signal SHfor performing the duty-reducing control of the normal motor-drivingpulses based on the generator AC magnetic-field detection result signalSC; and a correcting-driving-pulse output circuit 108 for determiningwhether a correcting driving pulse signal SJ is to be output, based onthe generator AC magnetic-field detection result signal SC and foroutputting the correcting driving pulse signal SJ if necessary.

The timepiece apparatus 1 further includes: a motor driving circuit 109for outputting a motor driving pulse signal SL for driving the pulsemotor 10, based on the normal motor-driving pulse signal SI or thecorrecting driving pulse signal SJ; a high-frequency magnetic-fielddetection circuit 110 for detecting a high-frequency magnetic fieldbased on an induction voltage signal SD output from the motor drivingcircuit 109 and for outputting a high-frequency magnetic-field detectionresult signal SE; an AC magnetic-field detection circuit 111 fordetecting an AC magnetic field based on the induction voltage signal SDoutput from the motor driving circuit 109 and for outputting an ACmagnetic-field detection result signal SF; a rotation detecting circuit112 for detecting whether the motor 10 is rotating based on theinduction voltage signal SD output from the motor driving circuit 109and for outputting a rotation-detecting result signal SG; and arotation-detecting control circuit 113 for outputting arotation-detecting control signal SM based on the generator ACmagnetic-field detection result signal SC output from the generator ACmagnetic-field detection circuit 106.

In this case, a high-frequency magnetic field is spiky electromagneticnoise, such as electromagnetic noise generated in turning on/off theswitches of household electrical appliances or a difference oftemperature controllers of electric blankets, and is irregularlygenerated.

An AC magnetic field is a magnetic field at 50 [Hz] or 60 [Hz] generatedfrom electrical appliances operated by commercial power, or is amagnetic field at a few hundred Hz to a few kHz generated by therotation of a motor, such as a shaver.

[1.3] Configuration of a Circuit Disposed Around Motor Driving Circuitand Rotation Detecting Circuit

FIG. 3 illustrates an example of a circuit disposed around the motordriving circuit and the rotation detecting circuit.

The motor driving circuit 109 is formed of a P-channel first transistorQ1 which is controlled to be on or off based on the normal motor-drivingpulse signal SI, a P-channel second transistor Q2 which is controlled tobe on or off based on the normal motor-driving pulse signal SI, anN-channel third transistor Q3 which is controlled to be on or off basedon the normal motor-driving pulse signal SI, and an N-channel fourthtransistor Q4 which is controlled to be on or off based on the normalmotor-driving pulse signal SI.

In this case, the first transistor Q1 and the fourth transistor Q4 aresimultaneously turned on or turned off based on the normal motor-drivingpulse signal SI.

The second transistor Q2 and the third transistor Q3 are simultaneouslyturned on or turned off in a manner opposite to the first transistor Q1and the fourth transistor Q4 based on the normal motor-driving pulsesignal SI.

The motor driving circuit 109 is also formed of induction voltagecontrollers 109A and 109B for controlling the voltage level of theinduction voltage generated in the motor 10 based on arotation-detecting pulse signal SN, a P-channel transistor Q5 forconnecting the high-potential power VDD to the induction voltagecontroller 109A based on the rotation-detecting pulse signal SN, and aP-channel transistor Q6 for connecting the high-potential power VDD tothe induction voltage controller 109B based on the rotation-detectingpulse signal SN.

Further, the rotation detecting circuit 112 is formed of a rotationdetecting circuit portion 112A for detecting the rotation when the motorcoil (not shown) of the pulse motor 10 is rotated in a first direction,and a rotation detecting circuit portion 112B for detecting the rotationwhen the motor coil (not shown) of the pulse motor 10 is rotated in asecond direction, which is opposite to the first direction.

The induction voltage controller 109A and the induction voltagecontroller 109B are described below with reference to FIG. 4. Since theconfigurations of the induction voltage controller 109A and theinduction voltage controller 109B are identical, only the inductionvoltage controller 109A is shown in FIG. 4.

The induction voltage controller 109A is formed of a switch SW which isconnected at one end to the drain D of the transistor Q5 and which isclosed (turned on) during the input period (input timing) of therotation-detecting pulse signal SN based on the rotation detectingcontrol signal SM, a first resistor RI (rotation-detecting impedancedevice) which is connected at one end to the drain D of the transistorQ5 and at the other end to one input terminal of the motor 10, and asecond resistor R2 (rotation-detecting impedance device) which isconnected at one end to the other end of the switch SW and at the otherend to a node between the first resistor RI and the input terminal ofthe motor 10.

[1.4] Operation of Timepiece Apparatus

A description is given below of the operation of the timepiece apparatus1 with reference to the flow chart of FIG. 5.

It is first determined whether one second has elapsed after thetimepiece apparatus 1 was reset or the previous driving pulse was output(step S10).

If it is determined in step S10 that one second has not elapsed, it isnot the time to output a driving pulse, and thus, the timepieceapparatus 1 enters a waiting state.

If it is determined in step S10 that one second has elapsed, it isdetermined by the charging detection circuit 102 whether charging causedby the power generation of the generator portion 101 has been detected(step S11).

If it is determined in step S11 that charging has been detected (stepS11; Yes), the detection of the rotation is controlled in such a mannerthat the impedance of the induction voltage controller 109A and theinduction voltage controller 109B becomes low (step S30), and theprocess proceeds to step S14. More specifically, the switch SW is turnedon by the rotation detecting control signal SM so as to connect thefirst resistor R1 and the second resistor R2 in parallel with eachother, so that the impedance (resistance value) of the combinedresistance of the first resistor R1 and the second resistor R2 iscontrolled to be lower than the impedance (resistance value) of thefirst resistor R1. The process then proceeds to step S14.

If it is found in step S11 that charging has not been detected (stepS11; No), it is determined whether a high-frequency magnetic field isdetected while a high-frequency magnetic-field detection pulse signalSP0 is being output (step S12)

[1.4.1] Processing to Be Performed when a High-frequency Magnetic Fieldis Detected While the High-frequency Magnetic-field Detection PulseSignal SP0 is Being Output

If it is determined in step S12 that a high-frequency magnetic field isdetected while the high-frequency magnetic-field detection pulse signalSP0 is being output (step S12; Yes), the output of the high-frequencymagnetic-field detection pulses SP0 is discontinued (step S23).

Subsequently, the outputs of AC magnetic-field detection pulses SP11 andAC magnetic-field detection pulses SP12 are discontinued (step S24), theoutput of normal driving-motor pulses K11 is discontinued (step S25),and the output of rotation detecting pulses SP2 is discontinued (stepS26).

Then, correcting driving pulses P2+Pr are output (step S27). In thiscase, in actuality, the correcting driving pulses P2 drive the pulsemotor 10, and the correcting driving pulses Pr are used for speedilyshifting the pulse motor to a steady state by inhibiting vibrationsafter the rotor is rotated after driving the pulse motor.

Then, in order to cancel a residual magnetic flux accompanied by anapplication of the correcting driving pulses P2+Pr, demagnetizing pulsesPE of the opposite polarity to the correcting driving pulses P2+Pr areoutput (step S28).

Subsequently, in performing pulse-width control, the duty ratio of thenormal driving pulses K11 is set so that power consumption can beminimized and the correcting driving pulses P2+Pr are not output (stepS29).

The process then returns to step S10, and processing similar to theabove-described processing is repeated.

[1.4.2] Processing to Be Performed when a High-frequency Magnetic Fieldis not Detected, and an AC Magnetic Field is Detected While the ACMagnetic-field Detection Pulses SP11 or the AC Magnetic-field DetectionPulses SP12 are Being Output

If it is determined in step S12 that a high-frequency magnetic field hasnot been detected while the high-frequency magnetic-field detectionpulse signal SP0 is being output (step S12; No), it is determinedwhether an AC magnetic field has been detected while the ACmagnetic-field detection pulses SP11 or the AC magnetic-field detectionpulses SP12 are being output (step S13).

If it is determined in step S13 that an AC magnetic field has beendetected while the AC magnetic-field detection pulses SP11 or the ACmagnetic-field detection pulses SP12 are being output (step S13; Yes),the outputs of the AC magnetic-field detection pulses SP11 and the ACmagnetic-field detection pulses SP12 are discontinued (step S24), theoutput of the normal driving-motor pulse K11 is discontinued (step S25),and the output of the rotation detecting pulses SP2 is discontinued(step S26). Thereafter, the correcting driving pulses P2+Pr are output(step S27).

Then, in order to cancel a residual magnetic flux accompanied by anapplication of the correcting driving pulses P2+Pr, demagnetizing pulsesPE of the opposite polarity to the correcting driving pulses P2+Pr areoutput (step S28).

Subsequently, the duty ratio of the normal driving pulses K11 is set sothat power consumption can be minimized and the correcting drivingpulses P2+Pr are not output (step S29).

The process then returns to step S10, and processing similar to theabove-described processing is repeated.

[1.4.3] Processing to be Performed when an AC Magnetic Field is notDetected While the AC Magnetic-field Detection Pulses SP11 or ACMagnetic-field Detection Pulses SP12 are Being Output

If it is determined in step S13 that an AC magnetic field has not beendetected while the AC magnetic-field detection pulses SP11 or the ACmagnetic-field detection pulses SP12 are being output (step S13; No),the normal driving pulses K11 are output (step S14).

It is then determined whether the rotation of the pulse motor has beendetected (step S15).

[1.4.4] Operation when the Rotation is not Detected

If it is determined in step S15 that the rotation of the pulse motor hasnot been detected, it is certain that the pulse motor is not rotated,and the correcting driving pulses P2+Pr are output (step S27).

Then, in order to cancel a residual magnetic flux accompanied by anapplication of the correcting driving pulses P2+Pr, demagnetizing pulsesPE of the opposite polarity to the correcting driving pulses P2+Pr areoutput (step S28).

Subsequently, the duty ratio of the normal driving pulses K11 is set sothat power consumption can be minimized and the correcting drivingpulses P2+Pr are not output (step S29).

The process then returns to step S11, and processing similar to theabove-described processing is repeated.

[1.4.5] Operation when the Rotation is Detected

If it is determined in step S11 that charging has been detected (stepS11; Yes), the rotation detecting circuit is selected (step S30), andthe normal driving pulses K11 are output (step S14).

Then, if it is found in step S15 that the rotation of the pulse motorhas been detected, it is determined that the pulse motor has beenrotated, and the output of the rotation detecting pulses SP2 isdiscontinued (step S16).

Subsequently, it is determined whether power generation for charging thestorage device 104 has been detected by the charging detection circuit102 (step S17).

[1.4.5.1] Operation in Detecting Power Generation After the NormalDriving Pulses are Output

If it is determined in step S17 that power generation for charging thestorage device 104 has been detected by the charging detection circuit102 (step S17; Yes), the duty-reducing counter for lowering the dutyratio so as to reduce the effective power of the normal motor-drivingpulses K11 is reset (set to a predetermined initialduty-reducing-counter value), or counting down of the duty-reducingcounter is discontinued (step S19).

Then, the above-described correcting driving pulses P2+Pr are output(step S20), in which case, correcting driving pulses P3+Pr′ having aneffective power greater than that of the correcting driving pulses P2+Prmay be output.

The correcting driving pulses P3+Pr′ may be output at a predeterminedtiming different from that of the correcting driving pulses P2+Pr. Thecorrecting driving pulses are output when power generation has beendetected in step S17 even though it is determined in step S15 that thepulse motor has been correctly rotated. The reason is as follows. Ifpower generation is performed after the normal driving pulses are outputin step S14, it cannot be determined in step S15 whether or not therotation is correctly detected, and it may erroneously detected.

Then, in order to cancel a residual magnetic flux accompanied by anapplication of the correcting driving pulses P3+Pr′, demagnetizingpulses PE′ of the polarity opposite to the correcting driving pulsesP3+Pr′ are output (step S21).

Upon completion of outputting the demagnetizing pulses PE′, the countingof the duty-reducing counter is restarted (step S22), and the duty ratioof the normal driving pulses K11 is set so that power consumption can beminimized and the correcting driving pulses P2+Pr and the correctingdriving pulses P3+Pr′ are not output.

The process then returns to step S10, and the processing similar to theabove-described processing is repeated.

[1.4.5.2] Operation when Power Generation is not Detected

If it is determined in step S17 that power generation for charging thestorage device 104 has not been detected by the generation detectingcircuit 102 (step S17; No), in performing pulse-width control, the dutyratio of the normal driving pulses K11 is set so that power consumptioncan be minimized and the correcting driving pulses P2+Pr are not output(step S18).

The process then returns to step S10, and processing similar to theabove-described processing is repeated.

[1.5] Example of Specific Operation

An example of the specific operation of the first embodiment isdescribed below with reference to the timing chart of FIG. 6.

At time t1, when the generator AC magnetic-field detection timing signalSB becomes an “H” level, the high-frequency magnetic-field detectionpulses SP0 are output from the motor driving circuit to the pulse motor10.

Then, at time t2, the AC magnetic-field detection pulses SP11 having afirst polarity are output from the motor driving circuit to the pulsemotor 10.

In this case, if the generated voltage of the generator portion 101exceeds the high-potential voltage VDD, the charging-detection resultsignal SA output from the charging detection circuit 102 becomes an “H”level, and the generator AC magnetic-field detection result signal SCbecomes an “H” level.

Thereafter, at time t3, the AC magnetic-field detection pulses SP12having a second polarity opposite to the first polarity are output, andat time t4, the output of the normal motor-driving pulses K11 isstarted.

Then, at time t5, since the generator AC magnetic-field detection resultsignal SC still remains at the “H” level, the rotation-detecting controlcircuit 113 changes the rotation-detecting control signal SM to an “H”level.

As a result, the induction voltage controllers 109A and 109B close (turnon) the switch SW for an input period (input timing) of therotation-detecting pulse signal SN, i.e., a predetermined period (fromtime t5 to time t10 in FIG. 6) including the input period of therotation detecting pulses SP2 based on the rotation-detecting controlsignal SM.

As a consequence, in the induction voltage controllers 109A and 109B,the impedance is decreased so as to shift the level of the inductionvoltage input into the rotation detecting circuit 112 to the no-rotationside, thereby reducing the influence of noise.

Thereafter, at time t6, when the generated voltage of the generatorportion 101 becomes lower than the high-potential voltage VDD, thecharging-detection result signal SA output from the charging detectioncircuit 102 becomes an “L” level.

Accordingly, at time t7, the generator AC magnetic-field detectionresult signal SC becomes an “L” level, and the output of the rotationdetecting pulses SP2 is completed.

As described above, if a high-frequency magnetic field is detectedduring the period from time t1 to time t4, and if an AC magnetic fieldis detected during the period from time t2 to time t4, or if therotation is not detected during the period from time t5 to time t7, thecorrecting driving pulses P2+Pr having an effective power greater thanthat of the normal driving pulses K11 are output at time t8 after thelapse of a predetermined period from the output start timing of thenormal driving pulses K11 (corresponding to time t4).

Accordingly, the pulse motor 10 can be reliably driven.

When the correcting driving pulses P2+Pr are output, the output ofdemagnetizing pulses PE of the polarity opposite to the correctingdriving pulses P2+Pr is started at time t9 in order to cancel a residualmagnetic flux accompanied by an application of the correcting drivingpulses P2+Pr.

Time t9 is set immediately before the subsequent external magnetic fieldis detected (the subsequent high-frequency magnetic-field detectionpulses SP0 are output).

The pulse width of the demagnetizing pulses PE to be output is narrow(short) enough so as not to rotate the rotor, and a plurality ofintermittent pulses (three pulses in FIG. 6) are provided to furtherenhance the demagnetizing effect.

At time t10, the generator AC magnetic-field detection result signal SCbecomes an “L” level, and the output of the demagnetizing pulses PE iscompleted.

Concurrently, the rotation-detecting control signal SM also becomes an“L” level, and the switches SW of the induction voltage controller 109Aand the induction voltage controller 109B are changed to the open state(turned off) so that the impedance of the induction voltage controller109A and the induction voltage controller 109B becomes as high as thatin the normal driving state.

As discussed above, in the rotation detecting period (time t5 to t7),the level of the induction voltage generated in the pulse motor 10according to the input of the rotation detecting pulses SP2 is shiftedto the no-rotation side.

Accordingly, even if the generation current generated by the powergeneration of the generator portion 101, and what is more, the voltagenoise caused by the charging current in charging the storage device 104,are superimposed on the induction voltage, the erroneous detection ofthe rotation of the no-rotation pulse motor 10 can be prevented.

As a result, the pulse motor 10 can be reliably driven.

[1.6] Advantages of First Embodiment

As is seen from the foregoing description, according to the firstembodiment, when charging is detected during the rotation detectingperiod of the rotation detecting circuit, the level of the inductionvoltage generated in the pulse motor upon inputting the rotationdetecting pulses is shifted to the no-rotation state. Accordingly, theerroneous detection of the rotation of the no-rotation pulse motor canbe prevented.

As a result, it is possible to ensure the reliable rotation of the pulsemotor, and the time can be accurately indicated in a timepieceapparatus.

[1.7] Examples of Modifications to First Embodiment

[1.7.1] First Example of Modifications

In the foregoing description of the first embodiment, in the inductionvoltage controller 109A and the induction voltage controller 109B, theswitch SW is turned on according to the rotation-detecting controlsignal SM so as to connect the first resistor R1 and the second resistorR2 in parallel with each other, whereby the combined impedance(resistance value) of the first resistor R1 and the second resistor R2is controlled to be lower than the impedance (resistance value) of thefirst resistor R1.

In contrast, in an induction voltage controller 109A′ of the firstexample of the modifications, a first resistor R1′ and a second resistorR2′ are connected in series to each other, as shown in FIG. 7, and aswitch SW′ is turned on according to the rotation-detecting controlsignal SM, thereby short-circuiting the terminals of the second resistorR2′.

Accordingly, the impedance (=R1) when the rotation is detected by therotation detecting circuit 112 is controlled to be lower than theimpedance (=R1′+R2′) when the rotation is not detected.

According to the configuration of the first example of themodifications, advantages similar to those offered by the firstembodiment can be obtained.

[1.7.2] Second Example of Modifications

In the first embodiment and the first example of the modifications, theimpedance control is performed according to whether the resistances arecombined. Alternatively, one or a plurality of impedance devices may beselected and connected to each other from a plurality of impedancedevices (resistors).

[1.7.3] Third Example of Modifications

In the first embodiment and the individual examples of themodifications, the impedance itself is controlled. However, a choppercurrent generated by the rotation detecting pulses flows in theabove-described impedance devices. Accordingly, a voltage drop device,such as a diode D1, is used instead of the second resistor R2′ of thefirst example of the modifications and is connected in series to theresistor R1′, as shown in FIG. 8, so as to turn on the switch SW″according to the rotation detecting control signal SM, therebyshorting-circuiting the terminals of the diode D1.

Thus, the induction voltage level when the rotation is detected by therotation detecting circuit 112 is controlled to be lower than that whenthe rotation is not detected by a voltage equal to the voltage drop ofthe diode D1.

According to the configuration of the third example of themodifications, advantages similar to those offered by the firstembodiment can be obtained.

[2] Second Embodiment

In the foregoing first embodiment, during the period in which therotation of the pulse motor is detected by the rotation detectingcircuit, the level of the induction voltage generated upon inputting therotation detecting pulses is shifted to the no-rotation detecting sideby reducing the impedance of the induction-voltage detection devices. Inthe second embodiment, however, the induction voltage level is shiftedto the no-rotation detection side by controlling the duty ratio of therotation detecting pulses.

[2.1] Principle of Second Embodiment

The principle of the second embodiment is first explained below withreference to FIG. 9.

FIG. 9 illustrates the relationship between the detection voltage(induction voltage) of the pulse motor upon inputting the rotationdetecting pulses and the duty ratio [%] of the rotation detectingpulses.

In FIG. 9, sign Vth indicates the rotation reference voltage fordetermining whether the pulse motor is rotating.

FIG. 9 shows that the peak of the detection voltage (induction voltage)of the pulse motor occurs in the vicinity of a 50 [%] (=½) duty ratio ofthe rotation detecting pulses.

If the detection voltage (induction voltage) of the pulse motor isrepresented by a detection voltage curve LA in the rotation state or adetection voltage curve LC in the no-rotation state, it can be easilyidentified by the rotation reference voltage Vth whether or not themotor is rotated.

On the other hand, as indicated by a detection voltage curve LB in theno-rotation state obtained during power generation, the detectionvoltage (induction voltage) is shifted to a high level (rotationdetecting side) because of a leakage magnetic flux caused by powergeneration.

As a result, the pulse motor is determined to be rotated even though itis not actually rotated, in which case, the time is indicated moreslowly in the timepiece apparatus.

Thus, in the second embodiment, in order to reduce the occurrence oferroneous detection, the duty ratio in the rotation detecting period isset to be higher or lower than that in the normal driving period.

More specifically, in contrast to the duty ratio of 50 [%] (=½) in thenormal driving period, the duty ratio in the rotation detecting periodis set to be 25 [%] (=¼) or 75 [%] (=¾) so that the detection voltage isshifted to a low level (no-rotation detection side), thereby preventingan erroneous detection.

[2.2] Functional Configuration of Control System

The functional configuration of the control system of the secondembodiment is described below with reference to FIG. 10.

In FIG. 10, symbols A through E correspond to the generator unit A, thepower supply unit B, the control unit C, the hand-moving mechanism D,and the driving unit E, respectively, shown in FIG. 1.

The timepiece apparatus 1 includes: a generator portion 101 forgenerating AC power; a charging detection circuit 102 for detectingcharging based on a generated voltage SK of the generator portion 101and for outputting a charging-detection result signal SA; a rectifiercircuit 103 for rectifying an alternating current output from thegenerator portion 101 and for converting it to a direct current; astorage device 104 for storing the direct current from the rectifiercircuit 103; and a timepiece control circuit 105, which is operated bythe electric energy stored in the storage device 104, for outputting thenormal motor-driving pulse signal SI for performing timepiece controland the rotation-detecting pulse signal SN used for rotation detection,and also outputting a generator AC magnetic-field detection timingsignal SB for designating the detection timing of the generator ACmagnetic field.

The timepiece apparatus 1 also includes: a generator AC magnetic-fielddetection circuit 106 for detecting the generator AC magnetic fieldbased on the charging-detection result signal SA and the generator ACmagnetic-field detection timing signal SB and for outputting a generatorAC magnetic-field detection result signal SC; a duty-reducing counter107 for outputting a normal-motor-driving-pulse duty-reducing signal SHfor controlling the duty-reducing of the normal motor-driving pulsesbased on the generator AC magnetic-field detection result signal SC; anda correcting-driving-pulse output circuit 108 for determining whether acorrecting driving pulse signal SJ is to be output, based on thegenerator AC magnetic-field detection result signal SC and foroutputting the correcting driving pulse signal SJ if necessary.

The timepiece apparatus 1 further includes: a motor driving circuit 109for outputting a motor driving pulse signal SL for driving the pulsemotor 10, based on the normal motor-driving pulse signal SI or thecorrecting driving pulse signal SJ; a high-frequency magnetic-fielddetection circuit 110 for detecting a high-frequency magnetic fieldbased on an induction voltage signal SD output from the motor drivingcircuit 109 and for outputting a high-frequency magnetic-field detectionresult signal SE; an AC magnetic-field detection circuit 111 fordetecting an AC magnetic field based on the induction voltage signal SDoutput from the motor driving circuit 109 and for outputting an ACmagnetic-field detection result signal SF; a rotation detecting circuit112 for detecting whether the motor 10 is rotating based on therotation-detecting pulse signal SN output from the timepiece controlcircuit 105 and the induction voltage signal SD output from the motordriving circuit 109 and for outputting a rotation-detecting resultsignal SG; and a rotation-detecting control circuit 113A for outputtinga rotation-detecting control signal SM based on the generator ACmagnetic-field detection result signal SC output from the generator ACmagnetic-field detection circuit 106.

[2.3] Specific Operation

The overall of the operation of the second embodiment is similar to thatof the first embodiment. Thus, an explanation thereof will be omitted,and the specific operation, in particular, the operation of therotation-detecting control circuit 113A, is discussed below.

FIG. 11 is a timing chart of the second embodiment.

FIG. 11(a) is a timing chart indicating the rotation-detecting controlsignal SM and the rotation-detecting pulse signal SN when charging isnot detected in the charging detection circuit 102.

As is seen from FIG. 11(a), when charging is not detected, that is, therotation-detecting control signal M is at an “L” level, the period ofthe rotation-detecting pulse signal SN is t1 having a 50 [%] (=½) dutyratio.

As a result, when the pulse motor is rotated, a detection voltagecorresponding to the detection voltage curve LA in the rotation state atthe 50 [%] duty ratio shown in FIG. 9 is obtained. When the pulse motoris not rotated, a detection voltage corresponding to the detectionvoltage curve LC in the no-rotation state at a duty ratio 50 [%] shownin FIG. 9 is obtained.

As a result, it can be easily detected whether or not the motor isrotated.

In contrast, when charging is detected, that is, the rotation-detectingcontrol signal SM is at an “H” level, as shown in FIG. 11(c), the periodof the rotation-detecting pulse signal SN is t1 having a 75 [%] (=¾)duty ratio.

As a result, when the pulse motor is rotated, a detection voltagecorresponding to the detection voltage curve LA in the rotation state atthe 75 [%] duty ratio is obtained. When the pulse motor is not rotated,a detection voltage corresponding to the detection voltage curve LB inthe no-rotation state at the 75 [%] duty ratio is obtained.

As a consequence, in this case, too, it is easily detected whether ornot the motor is rotated.

In the foregoing description, the duty ratio in the rotation detectingperiod is set to be higher than that in the normal driving period. Itmay be set to be lower than the duty ratio in the normal driving periodas long as it makes it easy to identify whether or not the motor isrotated.

[2.4] Advantages of Second Embodiment

As discussed above, according to the second embodiment, in the rotationdetecting period of the rotation detecting circuit, the duty ratio isset to be higher or lower than that in the normal driving period, sothat the level of the induction voltage generated in the pulse motorupon the input of rotation detecting pulses is shifted to theno-rotation side. Thus, the erroneous detection of the rotation of theno-rotation pulse motor can be prevented.

As a result, it is possible to ensure the reliable rotation of the pulsemotor, and the time is accurately indicated in a timepiece apparatus.

[2.5] Example of Modifications

In the foregoing second embodiment, in the rotation detecting period ofthe rotation detecting circuit, the duty ratio is set to be lower orhigher than that in the normal driving period. However, as shown in FIG.11(b), in the rotation detecting period of the rotation detectingcircuit, the duty ratio may be unchanged, and the period t2 of therotation detecting pulses may be set shorter than the period t1 of therotation detecting pulses in the normal driving period. In this case,advantages similar to the above-described advantages can be obtained.

In other words, if the duty ratio is unchanged and if the frequency ofthe rotation detecting pulses is set higher than that in the normaldriving period, the amplification factor of a chopper amplifier can bedecreased, in which case, advantages similar to the above-describedadvantages can be obtained.

More specifically, if the frequency of the rotation detecting pulses inthe normal driving period is 1 [kHz], the frequency of the rotationdetecting pulses in the rotation detecting period of the rotationdetecting circuit is increased to 2 [kHz].

[3] Third Embodiment

In the foregoing first and second embodiments, in the rotation detectingperiod of the pulse motor in the rotation detecting circuit, the levelof the induction voltage generated upon the input of the rotationdetecting pulses is shifted to the no-rotation detection side. In athird embodiment, however, the level of the induction voltage remainsthe same, and the voltage level of the rotation reference voltage (therotation reference voltage Vth in the second embodiment) is shifted tothe rotation detecting side so as to obtain advantages similar to theadvantages offered by the first and second embodiments.

[3.1] Functional Configuration of Control System

The functional configuration of the third embodiment is discussed belowwith reference to FIG. 12.

In FIG. 12, symbols A through E correspond to the generator unit A, thepower supply unit B, the control unit C, the hand-moving mechanism D,and the driving unit E, respectively, shown in FIG. 1.

The timepiece apparatus 1 includes: a generator portion 101 forgenerating AC power; a charging detection circuit 102 for detectingcharging based on a generated voltage SK of the generator portion 101and for outputting a charging-detection result signal SA; a rectifiercircuit 103 for rectifying an alternating current output from thegenerator portion 101 and for converting it to a direct current; astorage device 104 for storing the direct current output from therectifier circuit 103; and a timepiece control circuit 105, which isoperated by the electric energy stored in the storage device 104, foroutputting the normal motor-driving pulse signal SI for performingtimepiece control and also outputting a generator AC magnetic-fielddetection timing signal SB for designating the detection timing of thegenerator AC magnetic field.

The timepiece apparatus 1 also includes: a generator AC magnetic-fielddetection circuit 106 for detecting the generator AC magnetic fieldbased on the charging-detection result signal SA and the generator ACmagnetic-field detection timing signal SB and for outputting a generatorAC magnetic-field detection result signal SC; a duty-reducing counter107 for outputting a normal-motor-driving-pulse duty-reducing signal SHfor controlling the duty-reducing of the normal motor-driving pulsesbased on the generator AC magnetic-field detection result signal SC; anda correcting-driving-pulse output circuit 108 for determining whether acorrecting driving pulse signal SJ is to be output, based on thegenerator AC magnetic-field detection result signal SC, and foroutputting the correcting driving pulse signal SJ if necessary.

The timepiece apparatus 1 further includes: a motor driving circuit 109for outputting a motor driving pulse signal SL for driving the pulsemotor 10, based on the normal motor-driving pulse signal SI or thecorrecting driving pulse signal SJ; a high-frequency magnetic-fielddetection circuit 110 for detecting a high-frequency magnetic fieldbased on the induction voltage signal SD output from the motor drivingcircuit 109 and for outputting the high-frequency magnetic-fielddetection result signal SE; an AC magnetic-field detection circuit 111for detecting an AC magnetic field based on the induction voltage signalSD output from the motor driving circuit 109 and for outputting the ACmagnetic-field detection result signal SF; a rotation detecting circuit112C for detecting whether the motor 10 is rotated based on therotation-detecting control signal SM output from a rotation-detectingcontrol circuit 113B, which will be described below, and the inductionvoltage signal SD output from the motor driving circuit 109, and foroutputting the rotation-detecting result signal SG; and therotation-detecting control circuit 113B for outputting therotation-detecting control signal SM to the rotation detecting circuit112C based on the generator AC magnetic-field detection result signal SCoutput from the generator AC magnetic-field detection circuit 106.

[3.2] Rotation Detecting Circuit

FIG. 13 is a block diagram illustrating the circuit configuration of therotation detecting circuit 112C.

The rotation detecting circuit 112C is formed of: a rotation-detectingreference-voltage generating circuit 120 for generating arotation-detecting reference voltage Vth′ having a predetermined voltagelevel, based on the rotation-detecting control signal SM, insynchronization with a sampling signal SSMP output from the timepiececontrol circuit 105, and for outputting the rotation-detecting referencevoltage Vth′; and a comparator 121 for comparing the voltage level ofthe induction voltage signal SD with the voltage level of therotation-detecting reference voltage Vth′ in synchronization with thesampling signal SSMP input into an enable terminal EN and for outputtingthe rotation-detecting result signal SG.

FIG. 19 is a diagram illustrating the detailed configuration of therotation-detecting reference-voltage generating circuit 120.

The rotation-detecting reference-voltage generating circuit 120includes: resistors R11, R12, and R13 connected in series between ahigh-potential power supply VDD and a low-potential power supply VSS; anoutput terminal V0 connected to a node between the resistor R11 and theresistor R12 so as to output the rotation-detecting reference voltageSG; a rotation-reference-voltage switching transistor Tr11 whose drainis connected to a node between the resistor R12 and the resistor R13,whose source is connected to the low-potential power supply VSS, andwhose gate receives the rotation-detecting control signal SM; and aswitching transistor Tr12 whose drain is connected to the resistor R13,whose source is connected to the low-potential power supply VSS, andwhose gate receives the sampling signal SSMP, so that the switchingtransistor Tr12 is turned on in synchronization with the sampling signalSSMP so as to activate the rotation-detecting reference-voltagegenerating circuit 120.

The operation of the rotation-detecting reference-voltage generatingcircuit 120 is discussed below with reference to FIG. 20.

For reducing power consumption, the rotation detecting comparator 121and the rotation-detecting reference-voltage generating circuit 120 aredriven by the sampling signal SSMP in the rotation detecting period.

More specifically, in FIG. 20, the sampling signal SSMP becomes an “H”level while the rotation detecting pulses SP2 are being shifted to therotation detecting period in the transition timing from the “H” level tothe “L” level. In the period in which the sampling signal SSMP is in the“H” level (indicated by the hatched portions in FIG. 20), therotation-detecting reference-voltage generating circuit 120 is in theactive state.

When the rotation-detecting control signal SM is at the “L” level(corresponding to the no-rotation state), the rotation-reference-voltageswitching transistor Tr11 is in the off state, and the correspondingrotation-detecting reference voltage Vth′ is expressed by equation (1).In equation (1) and equation (2), the resistance values of the resistorsR11, R12, and R13 are represented by R11, R12, and R13, respectively,for convenience sake.

Vth′=Vth 1′=VSS×R 11/(R 11+R 12+R 13)  (1)

When the rotation-detecting control signal SM is in the “H” level(corresponding to the rotation detecting state), therotation-reference-voltage switching transistor Tr11 is in the on state,and the corresponding rotation-detecting reference voltage Vth′ isexpressed by equation (2).

Vth′=Vth 2′=VSS×R 11/(R 11+R 12)  (2)

Accordingly, the relationship between the rotation-detecting referencevoltages Vth1′ and Vth2′ obtained when the rotation-detecting controlsignal SM is at the “L” level and the “H” level, respectively, is:

Vth 1′<Vth 2′.

In this case, the rotation-detecting reference-voltage generatingcircuit 120 shifts the voltage level of the rotation-detecting referencevoltage Vth′ to the rotation detecting side when charging is detected,unlike the voltage level of the rotation-detecting reference voltageVth′ when charging is not detected.

[3.3] Specific Operation

An example of the specific operation of the third embodiment isdescribed below with reference to the timing chart of FIG. 14.

In the initial state, the rotation-detecting reference voltage Vth′ isset to a [V] (high-potential VDD reference).

At time t1, when the generator AC magnetic-field detection timing signalSB becomes an “H” level, the high-frequency magnetic-field detectionpulses SP0 are output from the motor driving circuit 109 to the pulsemotor 10.

Then, at time t2, the AC magnetic-field detection pulses SP11 having afirst polarity are output from the motor driving circuit to the pulsemotor 10.

At time t2, if the generated voltage of the generator portion 101exceeds the high-potential voltage VDD, the charging-detection resultsignal SA output from the charging detection circuit 102 becomes an “H”level, and the generator AC magnetic-field detection result signal SCbecomes an “H” level.

Thereafter, at time t3, the AC magnetic-field detection pulses S12having a second polarity, which is opposite to the first polarity, areoutput. At time t4, the output of the normal motor-driving pulses K11 isstarted.

Subsequently, since the generator AC magnetic-field detection resultsignal SC still remains at the “H” level, the rotation-detecting controlcircuit 113 changes the rotation-detecting control signal SM to the “H”level.

As a result, the rotation-detecting reference-voltage generating circuit120 of the rotation detecting circuit 112C compares the voltage level ofthe rotation-detecting reference voltage Vth′ with the voltage level (a[V]) when charging is not detected, based on the rotation-detectingcontrol signal SM, and shifts the voltage level of therotation-detecting reference voltage Vth′ to the rotation detectingside, i.e., shifts the rotation-detecting reference voltage Vth′ to thevoltage level b [V] (|a|<|b|).

Then, the comparator 121 compares the voltage level of the inductionvoltage signal SD with the voltage level (b [V]) of therotation-detecting reference voltage Vth′, and outputs therotation-detecting result signal SG.

Accordingly, the level of the induction voltage input into the rotationdetecting circuit 112A becomes effectively equal to the voltage levelwhich is shifted to the no-rotation side, thereby making it possible toreduce the influence of noise.

Thereafter, at time t6, when the generated voltage of the generatorportion 101 becomes lower than the high-potential voltage VDD, thecharging-detection result signal SA output from the charging detectioncircuit 102 becomes an “L” level.

Accordingly, at time t7, the generator AC magnetic-field detectionresult signal SC becomes an “L” level, and the output of the rotationdetecting pulses SP2 is also completed.

As described above, if a high-frequency magnetic field is detectedduring the period from time t1 to time t2, or if an AC magnetic field isdetected during the period from time t2 to time t4, or if the rotationis not detected during the period from time t5 to time t7, thecorrecting driving pulses P2+Pr having an effective power greater thanthat of the normal driving pulses K11 are output at time t8 after thelapse of a predetermined period from the output start timing of thenormal driving pulses K11 (corresponding to time t4).

Accordingly, the pulse motor 10 can be reliably driven.

When the correcting driving pulses P2+Pr are output, the output ofdemagnetizing pulses PE of the polarity opposite to the correctingdriving pulses P2+Pr is started at time t9 in order to cancel a residualmagnetic flux accompanied by an application of the correcting drivingpulses P2+Pr.

At time t10, the generator AC magnetic-field detection result signal SCbecomes an “L” level, and the output of the demagnetizing pulses PE iscompleted.

Concurrently, the rotation-detecting control signal SM also becomes an“L” level, and the switches SW of the induction voltage controller 109Aand the induction voltage controller 109B are changed to the open state(turned off) so that the rotation-detecting reference-voltage generatingcircuit 120 of the rotation detecting circuit 112A returns, based on therotation-detecting control signal SM, the voltage level of therotation-detecting reference voltage Vth′ to the voltage level (a [V])when charging is not detected.

As is seen from the foregoing description, in the rotation detectingperiod (time t5 to t7), the rotation-detecting reference voltage Vth′ tobe compared with the voltage level of the induction voltage generated inthe pulse motor 10 upon the input of the rotation detecting pulses SP2is shifted to the rotating side.

As a consequence, even if the generation current generated by powergeneration of the generator portion 101, and what is more, the voltagenoise caused by the charging current generated when the storage device104 is charged, are superimposed on the induction voltage, it ispossible to prevent the erroneous detection of the rotation of theno-rotation pulse motor 10.

As a result, the pulse motor 10 can be reliably driven.

[3.4] Advantages of the Third Embodiment

As discussed above, according to the third embodiment, in the rotationdetecting period of the rotation detecting circuit 112C, therotation-detecting reference voltage to be compared with the level ofthe induction voltage generated in the pulse motor upon the input of therotation detecting pulses is shifted to the rotating side. It is thuspossible to prevent the erroneous detection of the rotation of theno-rotation pulse motor 10.

It is thus possible to ensure the reliable rotation of the pulse motor,and the time is accurately indicated in a timepiece apparatus.

[4] Fourth Embodiment

In the foregoing embodiments, the level of the induction voltagegenerated in detecting the rotation relative to the rotation-detectingreference voltage is shifted. In a fourth embodiment, however, freevibrations of the no-rotation rotor of a pulse motor are inhibited so asto suppress the induction voltage level when the rotor is not rotated,thereby easily identifying whether or not the pulse motor is rotated.

[4.1] Functional Configuration of Control System

A description is given below of the functional configuration of acontrol system of the fourth embodiment with reference to FIG. 15.

In FIG. 15, symbols A through E correspond to the generator unit A, thepower supply unit B, the control unit C, the hand-moving mechanism D,and the driving unit E, respectively, shown in FIG. 1.

The timepiece apparatus 1 includes: a generator portion 101 forgenerating AC power; a charging detection circuit 102 for detectingcharging based on a generated voltage SK of the generator portion 101and for outputting a charging-detection result signal SA; a rectifiercircuit 103 for rectifying an alternating current output from thegenerator portion 101 and for converting it to a direct current; astorage device 104 for storing the direct current output from therectifier circuit 103; and a timepiece control circuit 105, which isoperated by the electric energy stored in the storage device 104, foroutputting the normal motor-driving pulse signal SI for performingtimepiece control and also for outputting a generator AC magnetic-fielddetection timing signal SB for designating the detection timing of thegenerator AC magnetic field.

The timepiece apparatus 1 also includes: a generator AC magnetic-fielddetection circuit 106 for detecting a generator AC magnetic field basedon the charging-detection result signal SA and the generator ACmagnetic-field detection timing signal SB and for outputting thegenerator AC magnetic-field detection result signal SC; a duty-reducingcounter 107 for outputting the normal-motor-driving-pulse duty-reducingsignal SH for performing duty-reducing control of the normalmotor-driving pulses based on the generator AC magnetic-field detectionresult signal SC; and a correcting-driving-pulse output circuit 108 fordetermining whether the correcting driving pulse signal SJ is to beoutput, based on the generator AC magnetic-field detection result signalSC, and for outputting the correcting driving pulse signal SJ ifnecessary.

The timepiece apparatus 1 further includes: a motor driving circuit 109for outputting the motor driving pulse signal SL for driving the pulsemotor 10, based on the normal motor-driving pulse signal SI or thecorrecting driving pulse signal SJ; a high-frequency magnetic-fielddetection circuit 110 for detecting a high-frequency magnetic fieldbased on the induction voltage signal SD output from the motor drivingcircuit 109 and for outputting the high-frequency magnetic-fielddetection result signal SE; an AC magnetic-field detection circuit 111for detecting an AC magnetic field based on the induction voltage signalSD output from the motor driving circuit 109 and for outputting the ACmagnetic-field detection result signal SF; a rotation detecting circuit112D for detecting whether the motor 10 is rotating based on therotation-detecting control signal SM output from a rotation-detectingcontrol circuit 113C, which will be described below, and the inductionvoltage signal SD output from the motor driving circuit 109, and foroutputting the rotation-detecting result signal SG; and therotation-detecting control circuit 113C for outputting therotation-detecting control signal SM to the timepiece control circuit105 based on the generator AC magnetic-field detection result signal SCoutput from the generator AC magnetic-field detection circuit 106.

[4.2] Specific Operation

An example of the specific operation of the fourth embodiment is nowdescribed with reference to the timing chart of FIG. 16.

In the normal driving period, the waveform of the normal motor-drivingpulse signal is formed of a plurality of pulses in a saw-tooth shape.Such a waveform is hereinafter referred to as a “saw-tooth waveform”.

At time t1, when the generator AC magnetic-field detection timing signalSB becomes an “H” level, the high-frequency magnetic-field detectionpulses SP0 are output from the motor driving circuit to the pulse motor10.

Then, at time t2, the AC magnetic-field detection pulses SP11 having afirst polarity are output from the motor driving circuit to the pulsemotor 10.

In this case, if the generated voltage of the generator portion 101exceeds the high-potential voltage VDD, the charging-detection resultsignal SA output from the charging detection circuit 102 becomes an “H”level, and the generator AC magnetic-field detection result signal SCbecomes an “H” level.

Thereafter, at time t3, the AC magnetic-field detection pulses SP12having a second polarity, which is opposite to the first polarity, areoutput.

At time t4, when the generator AC magnetic-field detection timing signalSB becomes an “L” level, the rotation-detecting control circuit 113Cchanges the rotation-detecting control signal SM to the “H” level.

As a result, the timepiece control circuit 105 shifts the waveform ofthe normal motor-driving pulse signal from the saw-tooth waveform(indicated by the one-dot chain lines in FIG. 16) to the rectangularwaveform (indicated by the solid lines in FIG. 16) having the same pulseoutput period as that of the saw-tooth waveform.

This makes it possible to raise the peak value of the current flowinginto the oil forming the pulse motor 10, thereby increasing the currentfalling time after the application of the normal motor-driving pulsesignal.

During the current falling time, the rotor forming the pulse motor 10 isnot rotated so as to inhibit the motion to return to the stable point bya togging torque. It is thus possible to suppress the induction voltagelevel in the no-rotation period.

More specifically, the normal motor-driving pulse signal having asaw-tooth waveform shown in FIG. 17(a) is changed to the normalmotor-driving pulse signal having a rectangular waveform shown in FIG.17(b). Accordingly, the current falling time t1 after the application ofthe normal motor-driving pulse signal is increased to t2, as shown inFIG. 17(d), thereby stopping the rotation of the rotor forming the pulsemotor 10. Thus, the motion to return to the stable point by a coggingtorque is greatly inhibited, thereby suppressing the induction voltagelevel when the motor is not rotated.

Thereafter, at time t5, the rotation detecting circuit 112D detects therotation based on the rotation detecting pulses SP2, in which case, thelevel of the induction voltage input into the rotation detecting circuit112D is shifted to the no-rotation side according to the current fallingtime. It is thus possible to reduce the influence of noise.

As discussed above, if a high-frequency magnetic field is detected inthe period from time t1 to t2, or if an AC magnetic field is detected inthe period from time t2 to t4, or if the rotation is not detected in theperiod from time t5 to t6, the correcting driving pulses P2+Pr having aneffective power greater than that of the normal driving pulses K11 areoutput at time t7 after the lapse of a predetermined period from theoutput start timing of the normal driving pulses K11 (corresponding totime t4).

Thus, the pulse motor 10 can be reliably driven.

When the correcting driving pulses P2+Pr are output, the output ofdemagnetizing pulses PE of the polarity opposite to the correctingdriving pulses P2+Pr is started at time t8 in order to cancel a residualmagnetic flux accompanied by the application of the correcting drivingpulses P2+Pr.

At time t9, the generator AC magnetic-field detection result signal SCbecomes an “L” level, and the output of the demagnetizing pulses PE iscompleted.

Concurrently, the rotation-detecting control signal SM also becomes an“L” level.

As is seen from the foregoing description, in the charging detectionperiod, since the waveform of the normal motor-driving pulses K11 ischanged from a saw-tooth waveform to a rectangular waveform, therotation of the rotor forming the pulse motor 10 is discontinued, andthe motion to return to the stable point by a cogging torque isinhibited. As a result, the effective induction voltage level in theno-rotation period is shifted to the no-rotation side.

As a consequence, even if the generation current generated by powergeneration of the generator portion 101, and what is more, the voltagenoise caused by the charging current generated when the storage device104 is charged, are superimposed on the induction voltage, it ispossible to prevent the erroneous detection of the rotation of theno-rotation pulse motor 10.

As a result, the pulse motor 10 can be reliably driven.

[4.3] Advantages of Fourth Embodiment

As discussed above, according to the fourth embodiment, in the rotationdetecting period of the rotation detecting circuit, the waveform of thenormal motor-driving pulses K11 is changed from a saw-tooth waveform toa rectangular waveform. Accordingly, the rotation of the rotor formingthe pulse motor 10 is discontinued, and electromagnetic braking isapplied to the motion to return to the stable point by a cogging torque,thereby shifting the effective induction voltage level in theno-rotation period to the no-rotation side. It is thus possible toprevent the erroneous detection of the rotation of the no-rotation pulsemotor.

As a result, the reliable rotation of the pulse motor can be ensured,and the time can be accurately indicated in a timepiece apparatus.

[4.4] Modification Examples

[4.4.1] First Example of Modifications

In the above description, the waveform of the normal motor-drivingpulses K11 is changed from a saw-tooth waveform to a rectangularwaveform. Instead of changing the waveform of the normal motor-drivingpulse signal to the rectangular waveform shown in FIG. 17(b), the widthof the last pulse of the normal motor-driving pulses K11 having asaw-tooth waveform is lengthened, as shown in FIG. 17(c). Accordingly,the current falling time t1 after the application of the normalmotor-driving pulse signal can be increased to time t3 (<t2), as shownin FIG. 17(e). This interrupts the rotation of the rotor forming thepulse motor 10, and strong electromagnetic braking is also applied tothe motion to return to the stable point by a cogging torque, therebysuppressing the induction voltage level in the no-rotation period.

[4.4.2] Second Example of Modifications

According to the above description, the rotation detecting pulses SP2are output immediately after the normal motor-driving pulses K11 areoutput. However, the rotation detecting pulses SP2 may be output afterthe lapse of a predetermined period from the output of the normalmotor-driving pulses K11, and the coil forming the pulse motor 10 may beset in the closed loop state during the predetermined period. This alsomakes it possible to apply electromagnetic braking, and advantagessimilar to the above-described advantages can be obtained.

[5] Fifth Embodiment

In the foregoing embodiments, a detection delay of the generationdetecting circuit is not considered. In a fifth embodiment, however, adetection delay of the generation detecting circuit is taken intoconsideration so as to prevent a detection leakage based on thedetection delay.

The functional configuration of the control system of the fifthembodiment is similar to that of the fourth embodiment shown in FIG. 12,except that a generation detecting circuit 12E is used instead of thegeneration detecting circuit of the fourth embodiment. A detailedexplanation will thus be omitted.

[5.1] Configuration of Circuits Located Close to Generation DetectingCircuit

An example of the configuration of the circuits located close to thegeneration detecting circuit which causes a detection delay is shown inFIG. 18.

FIG. 18 illustrates a generation detecting circuit 102E, and theperipheral circuits located near the generation detecting circuit 102E,that is, a generator portion 101 for generating AC power, a rectifiercircuit 103 for rectifying the alternating current output from thegenerator portion 101 and for converting it into a direct current, and astorage device 104 for storing the direct current output from therectifier circuit 103.

The generation detecting circuit 102E is formed of a NAND circuit 201for outputting the NAND of outputs of a first comparator COMP1 and asecond comparator COMP2, which will be discussed below, and a smoothingcircuit 202 for smoothing the output of the NAND circuit 201 by using anR-C integrating circuit and for outputting the smoothed output as thegeneration-detecting result signal SA.

The rectifier circuit 103 is formed of: a first comparator COMP1 forperforming on/off control of a first transistor Q1 by comparing thevoltage of one output terminal AG1 of the generator portion 101 with thereference voltage VDD so as to allow the first transistor Q1 to performactive rectification; a second comparator COMP2 for turning on/off asecond transistor Q2 alternately with the transistor Q1 by comparing thevoltage of the other output terminal AG2 of the generator portion 101with the reference voltage VDD so as to allow the second transistor Q2to perform active rectification; a third transistor Q3 which is turnedon when the terminal voltage V2 of the terminal AG2 of the generatorportion 101 exceeds a predetermined threshold voltage; and a fourthtransistor Q4 which is turned on when the terminal voltage V1 of theterminal AG1 of the generator portion 101 exceeds a predeterminedthreshold voltage.

First, the charging operation is described below.

When the generator portion 101 starts generating power, the generationvoltage is supplied to both the output terminals AG1 and AG2. In thiscase, the phase of the terminal voltage V1 of the output terminal AG1and the phase of the terminal voltage V2 of the output terminal AG2 areinverted with respect to each other.

When the terminal voltage V1 of the output terminal AG1 exceeds thethreshold voltage, the fourth transistor Q4 is turned on. Thereafter,when the terminal voltage V1 increases and exceeds the voltage of thepower supply VDD, the output of the first comparator COMPI becomes an“L” level so as to turn on the first transistor Q1.

On the other hand, since the terminal voltage V2 of the output terminalAG2 is below the threshold voltage, the third transistor Q3 is in theoff state, and the terminal voltage V2 is lower than the voltage of thepower supply VDD. Thus, the output of the second comparator COMP2 is atan “H” level, and the second transistor Q2 is in the off state.

Accordingly, while the first transistor Q1 is in the on state, thegeneration current flows in a path “terminal AG1→first transistor→powersupply VDD→storage device 104→power supply VTKN→fourth transistor Q4”,and the storage device 104 is charged.

Then, when the terminal voltage V1 of the output terminal AG1 drops andbecomes lower than the voltage of the power supply VDD, the output ofthe first comparator COMP1 becomes an “H” level, thereby turning off thefirst transistor Q1. Accordingly, the terminal voltage V1 of the outputterminal AG1 becomes less than the threshold voltage of the fourthtransistor Q4, thereby turning off the fourth transistor Q4.

In contrast, when the terminal voltage V2 of the output terminal AG2exceeds the threshold voltage, the third transistor Q3 is turned on.Then, when the terminal voltage V2 increases and exceeds the voltage ofthe power supply VDD, the output of the second comparator COMP2 becomesan “L” level, and the second transistor Q2 is turned on.

Accordingly, while the second transistor Q2 is in the on state, thegeneration current flows in a path “terminal AG2→second transistorQ2→power supply VDD→storage device 104→power supply VTKN→thirdtransistor Q3”, and the storage device 104 is charged.

As stated above, when the generation current flows, the output of thefirst comparator COMP1 or the second comparator COMP2 is at an “L”level.

Thus, the NAND circuit 201 of the generation detecting circuit 102Ecomputes a logical NAND of the outputs of the first comparator COMPI andthe second comparator COMP2, thereby outputting an “H”-level signal tothe smoothing circuit 202 while the generation current is flowing.

In this case, the output of the NAND circuit 201 contains switchingnoise, and thus, the smoothing circuit 202 smoothes the output of theNAND circuit 201 by using the R-C integrating circuit and outputs it asthe generation-detecting result signal SA.

The detection signal output from such a generation detecting circuit102E contains a detection delay because of its configuration.Accordingly, without considering this detection delay, the motor is notrotated correctly due to a detection leakage.

Thus, in the fifth embodiment, the motor is correctly rotated by takingthis detection delay into consideration.

[5.2] Advantages of Fifth Embodiment

As discussed above, according to the fifth embodiment, even with theoccurrence of a detection delay in the generation detecting circuit102E, when conditions for reliably outputting the correcting drivingpulses are met, that is, when power generation for charging the storagedevice 104 is detected by the generation detecting circuit 102E whilethe high-frequency magnetic-field detection pulses SP0, the ACmagnetic-field detection pulses SP11 and SP12, the normal driving pulsesK11, or the rotation detection pulses SP2 are being output, the outputof the pulses is discontinued, and the output of the subsequent pulsesis also inhibited. Thus, the rotation of the motor coil is reliablyensured by the correcting driving pulses. Accordingly, the need foroutputting the various pulses SP0, SP11, SP12, K11, and SP2 iseliminated since the reliable rotation of the motor is ensured by thecorrecting driving pulses, and power required for outputting thesepulses can thus be reduced.

Additionally, the generation detecting circuit 102E detects the presenceor the absence of power generation for charging the storage device 104via a path different from the charging path to the secondary cell. It isthus possible to simultaneously perform power generation detection andactual charging processing, and the charging efficiency is not lowered,which may otherwise be incurred upon detecting power generation.

[6.1] First Example of Modifications

In the foregoing description, when charging is detected in the chargingdetecting operation, the voltage level of the induction voltage or therotation reference voltage used for detecting the rotation is shifted sothat the erroneous detection of the rotation of the no-rotation motorcan be prevented. Instead of performing the charging detection or inaddition to the charging detection, control similar to theabove-described control may be performed in detecting a power-generationmagnetic field.

[6.2] Second Example of Modifications

In the foregoing embodiments, a single motor is controlled. If, however,a plurality of motors may be disposed in one environment, for example,if a plurality of motors are built in a wristwatch, they may besimultaneously controlled by a single generation detecting circuit(generator AC magnetic-field detection circuit).

[6.3] Third Example of Modifications

In the above-described embodiments, when a power-generation magneticfield is detected, the correcting driving pulses are output rather thanthe normal driving pulses. Alternatively, the output of the normaldriving pulses may not be prohibited, and the normal driving pulses maybe output prior to the output of the correcting driving pulses.

In this case, it is necessary to consider the polarity of both thedriving pulses so that the motor is driven to a correct position by thecorrecting driving pulses and the normal driving pulses rather thanbeing excessively driven. More specifically, the polarity of thecorrecting driving pulses is set to be the same as the normal drivingpulses. Accordingly, since the direction of the current flowing in themotor coil is the same, the polarity of the correcting driving pulses isopposite to the current direction corresponding to the direction inwhich the motor is subsequently rotated. Thus, even if the correctingdriving pulses are output by detecting power generation after the motoris rotated by the normal driving pulses, it is possible to prevent therotation of the motor caused by the correcting driving pulses after therotation of the motor by the normal driving pulses.

[6.4] Fourth Example of Modifications

As the generator portion of the present invention, any type of devicemay be applied, except when a power-generation magnetic-field isdetected instead of charging.

For example, electromagnetic generators in which a generation rotor isrotated by a crown or dynamic energy stored in a spring may be appliedto the generator portion of the present invention.

Alternatively, a system in which charging is performed by converting anexternal alternating magnetic field or an electromagnetic wave intoelectric energy by an induction coil may also be applied to thegenerator portion of the present invention.

[6.5] Fifth Example of Modifications

Although in the foregoing embodiments a wristwatch-type timepieceapparatus has been described by way of example, the present inventionmay be applied to any type of timepiece apparatus provided with a motorin which a magnetic field is generated during power generation, such asa pocket-type timepiece, a card-type portable timepiece, etc.

[6.6] Sixth Example of Modifications

Although in the above-described embodiments a wristwatch-type timepieceapparatus has been described by way of example, the present inventionmay be applied to any type of electronic apparatus provided with a motorin which a magnetic field is generated during power generation.

For example, the present invention may be applied to electronicapparatuses, such as music players, music recorders, image players andimage recorders (for CD, MD, DVD, magnetic tape), portable devicesthereof, computer peripheral devices (floppy disk drives, hard diskdrives, MO drives, DVD drives, printers, etc.) and portable devicesthereof.

[7] Advantages of Embodiments

According to the embodiments of the present invention, the voltage levelof the rotation detecting voltage is relatively shifted by apredetermined amount to a no-rotation side based on the generation stateof the generator portion and the charging state of the storage portion.The erroneous detection of the rotation of the no-rotation motor can beprevented, thereby making it possible to ensure the reliable rotation ofthe motor. Particularly in a timepiece apparatus, the time can beaccurately indicated.

What is claimed is:
 1. An electronic apparatus comprising: a powergenerator portion for performing power generation; a storage portion forstoring electric energy obtained by said power generation; at least onemotor driven by the electric energy stored in said storage portion; apulse driving controller for controlling the driving of said motor byoutputting a driving pulse signal; a rotation detecting portion fordetecting whether said motor has rotated by comparing a rotationdetecting voltage corresponding to an induction voltage generated insaid motor caused by the rotation of said motor with a rotationreference voltage; a state detecting portion for detecting a generationstate of said power generator portion or a charging state of saidstorage portion caused by said power generation; and a voltage settingportion for setting said rotation detecting voltage or said rotationreference voltage based on the generation state of said power generatorportion or said charging state of said storage portion detected by saidstate detecting portion so that a difference between said rotationdetecting voltage when said motor has not rotated and said rotationreference voltage is increased.
 2. An electronic apparatus according toclaim 1, wherein said voltage setting portion comprises a voltageshifting portion for relatively shifting the voltage level of saidrotation detecting voltage to a no-rotation side by a predeterminedamount.
 3. An electronic apparatus according to claim 1, wherein saidstate detecting portion comprises a charging detecting portion fordetecting whether said charging is being performed in said storageportion.
 4. An electronic apparatus according to claim 1, wherein saidstate detecting portion comprises a power-generation magnetic-fielddetecting portion for detecting whether a magnetic field has beengenerated by the power generation of said power generator portion.
 5. Anelectronic apparatus according to claim 2, wherein said rotationdetecting portion comprises a rotation-detecting impedance device, andsaid voltage shifting portion comprises an impedance reducing portionfor effectively reducing the impedance of said rotation-detectingimpedance device.
 6. An electronic apparatus according to claim 5,wherein said rotation-detecting impedance device comprises a pluralityof auxiliary rotation-detecting impedance devices, and saidimpedance-reducing portion effectively reduces the impedance of saidrotation-detecting impedance device by short-circuiting at least one ofsaid plurality of auxiliary rotation-detecting impedance devices.
 7. Anelectronic apparatus according to claim 5, wherein saidrotation-detecting impedance device comprises a plurality of auxiliaryrotation-detecting impedance devices, and said impedance-reducingportion effectively reduces the impedance of said rotation-detectingimpedance device by switching said plurality of auxiliaryrotation-detecting impedance devices.
 8. An electronic apparatusaccording to claim 5, wherein said rotation-detecting impedance devicecomprises a resistor device.
 9. An electronic apparatus according toclaim 1, further comprising a chopper amplifier portion for performingchopper amplification on said induction voltage and for outputting theamplified induction voltage as said rotation detecting voltage, whereinsaid voltage setting portion comprises an amplification-factor reducingportion for reducing an amplification factor of said chopper amplifierportion based on the generation state of said power generator portion orsaid charging state of said storage portion detected by said statedetecting portion.
 10. An electronic apparatus according to claim 9,wherein said amplification-factor reducing portion comprises avoltage-drop-device inserting portion for inserting a voltage dropdevice in a path of a chopper current generated by said chopperamplification.
 11. An electronic apparatus according to claim 9, whereinsaid chopper amplifier portion performs the chopper amplification at afrequency corresponding to a chopper-amplification control signal, andsaid amplification-factor reducing portion sets the frequency of saidchopper-amplification control signal in a detection period of apredetermined generation state or a predetermined charging state causedby said power generation to be higher by a predetermined amount thansaid chopper-amplification control signal in a no-detection period ofsaid predetermined generation state or said predetermined chargingstate.
 12. An electronic apparatus according to claim 9, wherein saidchopper amplifier portion sets a chopper duty in a detection period ofsaid charging to be greater or smaller than said chopper duty in ano-detection period of said charging, which is a reference chopper duty.13. An electronic apparatus according to claim 1, wherein said voltagesetting portion comprises a voltage shifting portion for shifting thevoltage level of said rotation reference voltage to a rotation side by apredetermined amount relative to said rotation detecting voltage basedon the generation state of said power generator portion or said chargingstate of said storage portion detected by said state detecting portion.14. An electronic apparatus according to claim 13, wherein said pulsedriving controller outputs a rotation-detecting pulse signal used fordetecting the rotation by said rotation detecting portion after thelapse of a predetermined period from an output of said driving pulsesignal, and said voltage shifting portion sets terminals of a coilforming said motor in a closed loop during said predetermined periodbased on the generation state of said power generator portion or thecharging state of said storage portion detected by said state detectingportion.
 15. An electronic apparatus according to claim 13, wherein saiddriving pulse signal comprises a plurality of auxiliary driving pulsesignals, and said voltage shifting portion sets an effective power ofthe last auxiliary driving pulse signal in an output period of saiddriving pulse signal to be greater than an effective power of the otherauxiliary driving pulse signal in the output period of said drivingpulse signal.
 16. An electronic apparatus according to claim 13, whereinsaid voltage shifting portion comprises a reference-voltage selectingportion for selecting one of a plurality of basic rotation referencevoltages as said rotation reference voltage based on the generationstate of said power generator portion or the charging state of saidstorage portion detected by said state detecting portion.
 17. Anelectronic apparatus according to claim 16, wherein said state detectingportion detects said charging state based on a charging current flowingin said storage portion.
 18. An electronic apparatus according to claim16, wherein said state detecting portion detects said charging statebased on a charging voltage of said storage portion.
 19. An electronicapparatus according to claim 2, wherein said pulse driving controlleroutputs a rotation-detecting pulse signal used for detecting therotation by said rotation detecting portion after the lapse of apredetermined period from an output of said driving pulse signal, andsaid voltage shifting portion sets terminals of a coil forming saidmotor in a closed loop during said predetermined period based on thegeneration state of said power generator portion or the charging stateof said storage portion detected by said state detecting portion.
 20. Anelectronic apparatus according to claim 19, wherein said voltageshifting portion sets a frequency of said driving pulse signal in adetection period of a predetermined generation state or a predeterminedcharging state to be lower than a frequency in a no-detection period ofsaid predetermined generation state or said predetermined charging statebased on the generation state of said power generator portion or thecharging state of said storage portion detected by said state detectingportion.
 21. An electronic apparatus according to claim 2, wherein saiddriving pulse signal comprises a plurality of auxiliary driving pulsesignals, and said voltage shifting portion sets an effective power ofthe last auxiliary driving pulse signal in an output period of saiddriving pulse signal to be greater than an effective power of the otherauxiliary driving pulse signal in the output period of said drivingpulse signal.
 22. An electronic apparatus according to claim 1, whereinsaid electronic apparatus is portable.
 23. An electronic apparatusaccording to claim 1, wherein said electronic apparatus comprises atimepiece portion for performing a timing operation.
 24. A controlmethod for an electronic apparatus which comprises a power generatorportion for performing power generation, a storage portion for storingelectric energy obtained by said power generation, at least one motordriven by the electric energy stored in said storage portion, and apulse driving controller for controlling the driving of said motor byoutputting a driving pulse signal, said control method comprising: arotation detecting step of detecting whether said motor has rotated bycomparing a rotation detecting voltage corresponding to an inductionvoltage generated in said motor caused by the rotation of said motorwith a rotation reference voltage; a state detecting step of detecting ageneration state of said power generator portion or a charging state ofsaid storage portion caused by said power generation; and a voltageshifting step of shifting the voltage level of said rotation detectingvoltage to a no-rotation side by a predetermined amount relative to saidrotation reference voltage based on the generation state of said powergenerator portion or the charging state of said storage portion detectedin said state detecting step.
 25. A control method for an electronicapparatus which comprises a power generator portion for performing powergeneration, a storage portion for storing electric energy obtained bysaid power generation, at least one motor driven by the electric energystored in said storage portion, and a pulse driving controller forcontrolling the driving of said motor by outputting a driving pulsesignal, said control method comprising: a rotation detecting step ofdetecting whether said motor has rotated by comparing a rotationdetecting voltage corresponding to an induction voltage generated insaid motor caused by the rotation of said motor with a rotationreference voltage; a state detecting step of detecting a generationstate of said power generator portion or a charging state of saidstorage portion caused by said power generation; and a voltage shiftingstep of shifting the voltage level of said rotation reference voltage toa rotation side by a predetermined amount relative to said rotationdetecting voltage based on the generation state of said power generatorportion or the charging state of said storage portion detected in saidstate detecting step.
 26. An electronic apparatus comprising: agenerator for generating power; a storage element for storing powergenerated by the generator; a motor driven by the electric energy storedin the storage element; a pulse driving controller for controlling thedriving of the motor by outputting a driving pulse signal; and arotation detector for detecting whether the motor has rotated bycomparing a rotation detection voltage corresponding to an inductionvoltage generated in the motor caused by its rotation with a rotationreference voltage; a state detecting unit for detecting a generationstate of the generator or a charging state of the storage element; and avoltage setter for setting the rotation detecting voltage or therotation reference voltage based on the generation state of thegenerator or the charging state of the storage element; wherein, a casein which rotation of the motor is detected by the rotation detector,either (i) the level of the induction voltage generated on inputtingrotation detecting pulses is shifted to a no-rotation detecting side, or(ii) the level of the rotation reference voltage is shifted to arotation detecting side.
 27. An electronic apparatus according to claim26, wherein the level of the induction voltage generated on inputtingrotation detecting pulses is shifted to the no-rotation detecting sideby reducing impedance of a portion of the rotation detector.
 28. Anelectronic apparatus according to claim 26, wherein the level of theinduction voltage generated on inputting rotation detecting pulses isshifted to the no-rotation detecting side by controlling the duty ratioof the rotation detecting pulses.
 29. An electronic apparatuscomprising: a generator for generating power; a storage element forstoring power generated by the generator; a motor having a rotor drivenby the electric energy stored in the storage element; a pulse drivingcontroller for controlling the driving of the motor by outputting adriving pulse signal; and a rotation detector for detecting whether themotor has rotated by comparing a rotation detection voltagecorresponding to an induction voltage generated in the motor caused byits rotation with a rotation reference voltage; and a state detectingunit for detecting a generation state of the generator or a chargingstate of the storage element; wherein, free vibrations of the rotor areinhibited so as to suppress the induction voltage level, when generationof the generator or a charging of the storage element is detected by thestate detecting unit.